Carburetor



Oct. 26, 1965 H. T. M. RICE 3,214,150

GARBURETOR Filed July 3, 1961 V T 39 \Of /2 INVENTOR.

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United States Patent 3,214,150 CAIRBURETQR Henry T. M. Rice, San Gabriel, Calif, assignor to (thlsson 8: Rice, Inc, Los Angeles, Calif, a corporation of California Filed July 3, 1961, Ser. No. 121,514 Claims. (Cl, 2t$1-62) The present invention relates to charge-forming devices, and more particularly to carburetors for internal combustion engines.

In internal combustion engines, only a small quantity of fuel is required for delivery to the engine cylinder or cylinders during idling. The supply of such small amount of fuel is usually accomplished by feeding the fuel through a relatively small idling jet or passage, Which is separate from the normal operating jet or nozzle. Because of the small hole size of such idling jet or passage, its tendency to clog becomes pronounced. Such clogging tendency increases considerably in carburetors for small horsepower engines, such as one or two horsepower, or less, in which the idling jet hole size must be made comparatively minute or less in diameter than even a small hole size in an idling jet for an engine of much greater horsepower. Clogging or restriction of the idling jet or passage obviously results in stalling of the engine.

An object of the present invention is to provide a carburetor that avoids the use of small size jets or passages for supplying fuel sufficient for engine idling, or under conditions in which the throttle valve or plate is substantially fully closed.

Another object of the invention is to reduce the num- 'ber of jets in a carburetor by using one of the normal operating jets for supplying fuel under engine idling conditions, as well as during normal operation of the engine.

A further object of the invention is to provide a car buretor in which the jet for feeding fuel to an internal combustion engine under load is also used to feed the proper quantity of fuel to the engine under no-l-oad or idling conditions, and in which the proper air-fuel ratio is maintained during idling or no-load conditions.

An additional object of the invention is to provide a carburetor for internal combustion engines having comparatively few parts, which are economical to manufacture and easy to assemble, but which are still sturdy and dependable.

This invention possesses many other advantages, and has other objects which may be made more clearly apparent from a consideration of a form in which it may be embodied. This form is shown in the drawings accompanying and forming part of the present specification. It will now be described in detail, for the purpose of illustrating the general principles of the invention; but it is to be understood that such detailed description is not to be taken in a limiting sense, since the scope of the invention is best defined by the appended claims.

Referring to the drawings:

FIGURE 1 is a longitudinal section through a portion of a carburetor embodying the invention;

FIG. 2 is a section taken along the line 2-2 on FIG. 1;

FIG. 3 is a section taken along FIG. 2;

The charge-forming or carburetor device illustrated in the drawings includes a main carburetor body having an inlet passage 11 for air adapted to flow into the up stream side of the venturi 12 of the carburetor, admixing with fuel in the carburetor so that the air-fuel mixture passes through the venturi outlet 13 and then to an engine cylinder or cylinders (not shown). A suitable liquid fuel stems from a suitable source (not shown), which may the line 33 on then flow through a suitable demand fuel regulator 14, or the like, this fuel then passing into a fuel inlet or passage 15 controlled by an adjustable needle valve 16 threaded into the carburetor body it). The needle valve may have a knurled head 17 to facilitate its adjustment in the carburetor inlet 15 to provide the proper restriction in the fuel inlet passage 15, the needle valve remaining in its adjusted position because of a helical compression spring 18 hearing against the head 17 and against the carburetor body 10.

The fuel flows from the inlet passage 15' into a transverse bore 19 in the carburetor body, which is threaded to threadedly receive a carburetor jet or nozzle 20 projecting through an aligned bore 21 in the body, and with its inner portion 22 extending partially into the throat 23 of the venturi. Fuel from the inlet 15 passes into the bore 19 and through the carburetor jet passage 24 into the throat portion 23 of the carburetor. Air drawn through the carburetor body and its venturi 12, by the suction developed by the engine, flows past the outlet end 25 of the carburetor jet 20, drawing fuel therefrom, which admixes with the air, the mixture passing to the engine cylinder or cylinders. The quantity of air flowing is dependent upon the position of a throttle plate 26 mounted on a rod 27 rotatable in aligned bores 28 in the carburetor body it}, and projecting in opposite directions therefrom. The threaded bore 19 in the carburetor body has its outer end closed by a suitable screw plug 29, which may also attach the demand fuel regulator 14 to the carburetor body 10, as specifically described in the application of Henry T. M. Rice for Demand Fuel Regulator, Serial No. 108,647, filed May 8, 1961, now Patent No. 3,151,627.

The throttle plate 26 is fastened to the rod 27 in a relatively simple manner. As shown in the drawings, the rod has a slot 30 extending inwardly therefrom from one end 31 by a substantial distance. The slot 30 has a width conforming to the thickness of the throttle plate 26, and the throttle plate has a notch 32 through one portion slightly wider than the diameter of the rod 27. Accordingly, the throttle plate 26 can be slipped into the rod 27 from the open end 31 of the slot 30 to the fullest extent, in which the base 33 of the notch engages the inner end 34 of the slot. The throttle plate 26 is circular and has a diameter conforming to the diameter of the venturi throat 23, so that when disposed in a position normal to the axis of the venturi, the latter is almost fully closed.

The throttle plate 26 is norm-ally biased to an open position by a coil spring 35 encompassing an outer portion 36 of the rod, and which has one end secured thereto, as by inserting it into a transverse hole 37 in the rod. The other end 33 of the coil spring is secured to or bears upon a pin or projection 39 fixed to the carburetor body it The spring 35 tends to turn the rod 27 in one direction, as in a counter-clockwise direction as seen in FIG. 1, to remove the throttle plate as from the position shown in FIG. 1 normal to the axis of the venturi 12 toward a position substantially inclined to the axis of the venturi, thereby allowing a greater quantity of air at a greater velocity to flow through the venturi, which will ass across the open end 25 of the carburetor nozzle 20 and create a suction therewithin, pulling liquid fuel from the jet passage 24 into the carburetor throat 23 for admixture with the air.

The rod 27 is prevented from moving endwise of the carburetor body It by a throttle lever 40 mounted over an end portion 41 of the rod of reduced diameter, so as provide a shoulder 42 against which the throttle lever abuts. The throttle lever 40 is secured to the rod 27, as illustrated in the drawings, by outwardly flaring the ends inf the rod on opposite sides of the slot and forcing them against the outer surface of the throttle lever 40, clamping the latter against the rod shoulder 42. Accordingly, the throttle lever 40 prevents endwise movement of the rod 27 in one direction, as to the left as seen in FIGS. 2 and 3, by engaging the body 10, whereas the coil spring resists movement of the rod in the opposite direction. Such movement of the rod 27 will also be resisted by engagement of the throttle plate 26 with the side wall of the venturi 12.

The throttle lever may have a push pad 44 projecting therefrom against which a suitable manual operating member, such as a rod (not shown), may bear. When a force is exerted on such push rod, it bears against the pad 44 and rocks the lever 4t and rod 27 in a direction to shift the throttle plate 26 toward a closed position (FIG. 1). Release of the force on the throttle lever allows the coil spring 35 to move the rod 27 and throttle plate 26 to the full throttle open position.

In addition to actuation of the rod 27 and throttle plate 26 by the throttle lever 44), it may also be actuated by a shaft extending to a suitable governor (not shown). This shaft is coaxial of the throttle rod 27 and has its end portion 46 flat and of a thickness conforming to the width of the rod slot 30, which allows the flat portion to be inserted readily between the flared ends 43 of the rod and into the same slot 30 that has received the throttle plate 26. The slotted rod arrangement, therefore, accomplishes at least three purposes. It serves as an economical and effective manner of attaching the throttle plate 26 to the rod 27; it serves to allow the outer ends 43 of the rod to be flared and clamp the throttle lever 40 against the rod shoulder 42; and it also functions to permit the easy coupling of the fiat portion 46 of the governor shaft 45 to the rod 27. Although not disclosed herein, the governor will operate to turn the rods 45 and 27 against the force of the spring 35 to shift the throttle plate 26 toward a closed position, as when the engine speed tends to increase. Decrease in the engine speed below the desired value allows the coil spring 35 to turn the rod 27 and governor shaft 45 in a direction to shift the throttle plate 26 to a more fully opened position.

The carburetor jet passage 24 is of a sufiicient size as to insure the proper supply of fuel to the venturi throat 23 and to the engine under full-load conditions, as well as under partial-load conditions. This same jet also c0- acts with the throttle plate 26 to insure the proper supply of fuel to the engine necessary for idling or no-load conditions of the engine. As shown, the throttle plate 26 is mounted for movement about an axis extending across the venturi throat 23, and, in fact, the throttle plate is disposed fully within and extends across the venturi throat when in the closed position illustrated in the drawings. The throttle plate has a recess 50 of a width slightly greater than the diameter of the portion 22 of the carburetor jet or nozzle 20 projecting into the venturi 12, the base 51 of the recess being disposed away from the end 25 of the carburetor jet by a slight amount when the throttle plate 26 is in its fully closed position. Accordingly, with the throttle plate in the closed position, some air can still pass from the inlet passage 11 through the gap 52 between the end 25 of the carburetor jet and the base 51 of the recess 50 in the throttle plate 26, and such air will create a suction in the jet 2t) sufficient to draw a supply of fuel through the jet passage 24 adequate for admixture with the air and for maintaining the engine operating at an idling rate of speed. Because of the coaction between the throttle plate 26 and the carburetor jet 20 in limiting the quantity of air that can pass across the end or mouth 25 of the carburetor nozzle 2%), only the proper amount of fuel for idling is drawn through the nozzle 20. However, when the throttle plate 26 is shifted toward a fully open condition, a much greater area for the passage of air across the end 25 of the carburetor jet 20 exists, so that the increased flow of air draws an increased quantity of fuel through the jet 20 for admixture with the air and for supply to the engine cylinder or cylinders.

The carburetor jet passage 24 is comparatively large and is, therefore, not susceptible to clogging or restriction by foreign particles. It insures the provision of the proper air-fuel ratio during engine operation under load, and it also enables the proper air-fuel ratio to be provided during idling conditions depending upon the gap or distance 52 between the end 25 of the jet or nozzle 20 and the base 51 of the throttle plate recess 50, which determines the area of the passage through which air is drawn by the engine. The throttle plate 26 acts as a bafiie and coacts with the carburetor jet 20 to reduce the suction at the jet when the throttle plate 26 is in its idling position, such as illustrated in the drawings. Shifting of the plate 26 from such position, as noted above, greatly increases the effective area for the passage of air across the outlet 25 of the jet and results in an increased suction, which will draw an increased amount of fuel through the jet passage 24 and into the carburetor venturi 12. The coaction between the throttle plate 26 and the carburetor jet 2t) enables a single jet with a large passage area to function to supply the proper amount of fuel for engine idling conditions, as well as for load conditions, ranging from no-load to full-load.

I claim:

1. In a carburetor for an internal combustion engine: a body having a venturi through which air can flow; a nozzle in said body projecting into the throat portion of the venturi for feeding fuel thereinto; and a throttle plate in said throat portion pivotally mounted in said body and adapted to occupy positions opening said throat portion and a maximum position across said throat portion to substantially fully close the same; said plate having a recess extending inwardly from the periphery of said plate and displaced arcuately from the pivot axis of said plate, the plate having an inner base defining the inner end of said recess, said nozzle projecting into said recess, and spaced from said base to define a gap therebetween when said plate is in its maximum closed position, whereby air flows through said gap to draw fuel from said nozzle.

2. In a carburetor for an internal combustion engine: a body having a venturi through which air can flow; a nozzle in said body projecting into the throat portion of the venturi for feeding fuel thereinto; a rod extending across said throat portion and pivotally mounted in said body, said rod having a slot opening through an end of said rod; a throttle plate in said slot adapted to be inserted thereinto through said end and secured to said rod for pivotal movement in said venturi with said rod between positions opening said throat portion and a posi tion across said throat portion to substantially fully close the same; said plate having a recess extending inwardly from the periphery of said plate, the plate having an inner base defining the inner end of said recess, said nozzle projecting into said recess and spaced from said base to define a gap therebetween when said plate is in its substantially fully closed position, whereby air flows through said gap to draw fuel from said nozzle; an operating member mounted on said rod; said rod at opposite sides of said slot at said end flaring outwardly and bearing against said operating member to secure said operating member to said rod.

3. In a carburetor for an internal combustion engine: a body having a venturi through which air can flow; a nozzle in said body projecting into the throat portion of the venturi for feeding fuel thereinto; a rod extending across said throat portion and pivotally mounted in said body, said rod having a slot opening through an end of said rod; a throttle plate in said slot adapted to be inserted thereinto through said end and secured to said rod for pivotal movement in said venturi with said rod between positions opening said throat portion and a position across said throat portion to substantially fully close the same; said plate having a recess extending inwardly from the periphery of said plate, the plate having an inner base defining the inner end of said recess, said nozzle projecting into said recess and spaced from said base to define a gap therebetween when said plate is in its substantially fully closed position, whereby air flows through said gap to draw fuel from said nozzle; an operating member extending through said end into said slot for pivotally moving said rod and plate in said body; another operating member mounted on said rod; said rod at opposite sides of said slot at said end flaring outwardly and bearing against said another operative member to secure said another operating member to said rod.

4. In a carburetor for an internal combustion engine: a body having a passage through which fluid can flow; a rod extending across said passage and pivotally mounted in said body, said rod having a slot opening through an end of said rod; a throttle plate in said slot adapted to be inserted thereinto through said end and secured to said rod for pivotal movement in said passage between positions opening and substantially fully closing said passage; an operating member mounted on said rod; said rod at opposite sides of said slot at said end flaring outwardly and bearing against said operating member to secure said operating member to said rod.

5. In a carburetor for an internal combustion engine: a body having a passage through which fluid can flow; a rod extending across said passage and pivotally mounted in said body, said rod having a slot opening through an end of said rod; a throttle plate in said slot adapted to be inserted thereinto through said end and secured to said rod for pivotal movement in said passage between positions opening and substantially fully closing said passage; an operating member extending through said end into said slot for pivotally moving said rod and plate in said body; another operating member mounted on said rod; said rod at opposite sides of said slot at said end flaring outwardly and bearing against said another operating member to secure said another operating member to said rod.

References Cited by the Examiner UNITED STATES PATENTS 1,780,522 11/30 Hammer et al 261-62 3,004,242 6/35 Heitger 26l64 X 2,105,343 1/38 Briggs 251-308 2,407,534 9/46 Carlson 26144 2,538,569 1/51 Kittler et al. 261-62 FOREIGN PATENTS 362,315 11/22 Germany. 194,842 3/23 Great Britain.

HARRY B. THORNTON, Primary Examiner.

HERBERT L. MARTIN, Examiner. 

1. IN A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE: A BODY HAVING A VENTURI THROUGH WHICH AIR CAN FLOW; A NOZZLE IN SAID BODY PROJECTING INTO THE THROAT PORTION OF THE VENTURI FOR FEEDING FUEL THEREINTO; AND A THROTTLE PLATE IN SAID THROAT PORTION PIVOTALLY MOUNTED IN SAID BODY AND ADAPTED TO OCCUPY POSITIONS OPENING SAID THROAT PORTION AND A MAXIMUM POSITION ACROSS SAID THROAT PORTION TO SUBSTANTIALLY FULLY CLOSE THE SAME; SAID PLATE HAVING A RECESS EXTENDING INWARDLY FROM THE PERIPHERY OF SAID PLATE AND DISPLACED ARCUATELY FROM THE PIVOT AXIS OF SAID PLATE, THE PLATE HAVING AN INNER BASE DEFINING THE INNER END OF SAID RECESS, SAID NOZZLE PROJECTING INTO SAID RECESS, AND SPACED FROM SAID BASE TO DEFINE A GAP THEREBETWEEN WHEN SAID PLATE IS IN ITS MAXIMUM CLOSED POSITION, WHEREBY AIR FLOWS THROUGH SAID GAP TO DRAW FUEL FROM SAID NOZZLE.
 4. IN A CARBURETOR FOR AN INTERNAL COMBUSTION ENGINE: A BODY HAVING A PASSAGE THROUGH WHICH FLUID CAN FLOW; A ROD EXTENDING ACROSS SAID PASSAGE AND PIVOTALLY MOUNTED IN SAID BODY, SAID ROD HAVING A SLOT OPENING THROUGH AN END OF SAID ROD; A THROTTLE PLATE IN SAID SLOT ADAPTED TO BE INSERTED THEREINTO THROUGH SAID END AND SECURED TO SAID ROD FOR PIVOTAL MOVEMENT IN SAID PASSAGE BETWEEN POSITIONS OPENING AND SUBSTANTIALLY FULLY CLOSING SAID PASSAGE; AN OPERATING MEMBER MOUNTED ON SAID ROD; SAID ROD AT OPPOSITE SIDES OF SAID SLOT AT SAID END FLARING OUTWARDLY AND BEARING AGAINST SAID OPERATING MEMBER TO SECURE SAID OPERATING MEMBER AT SAID ROD. 